Same pattern as Average height — a class of 40 pupils. New numbers, new story. Try each one on paper, then check the working below — or watch it drawn out, the same way the problem above is.
Question 1
The gardening club measures the plants it has grown. The average height of the 3 plants in the Sunflower group is 55 cm. The average height of the 5 plants in the Marigold group is 47 cm. What is the average height of all 8 plants?
Work it out on paper, then check below. ▶ See the working
Question 2
Two houses collect old newspapers for a recycling drive. The average amount collected by the 2 pupils in Blue House is 53 kg. The average amount collected by the 6 pupils in Red House is 49 kg. What is the average amount collected by all 8 pupils?
Work it out on paper, then check below. ▶ See the working
Question 3
Two families compare pocket money. The 5 children in the Tan family get 34 dollars a week on average. The 4 children in the Lim family get 25 dollars a week on average. What do all 9 children get on average?
Work it out on paper, then check below. ▶ See the working
Question 4
Two families compare pocket money. The 5 children in the Tan family get 30 dollars a week on average. All 8 children together get 24 dollars a week on average. What do the Lim children get on average?
Work it out on paper, then check below. ▶ See the working
Question 5
Two families compare pocket money. The 5 children in the Tan family get 15 dollars a week on average. The 3 children in the Lim family get 7 dollars a week on average. What do all 8 children get on average?
Work it out on paper, then check below. ▶ See the working
Question 6
Two families compare pocket money. The 3 children in the Tan family get 22 dollars a week on average. All 5 children together get 20 dollars a week on average. What do the Lim children get on average?
Work it out on paper, then check below. ▶ See the working
Question 7
Two families compare pocket money. The 2 children in the Tan family get 26 dollars a week on average. The 6 children in the Lim family get 18 dollars a week on average. What do all 8 children get on average?
Work it out on paper, then check below. ▶ See the working
Question 8
Two families compare pocket money. The 2 children in the Tan family get 23 dollars a week on average. The 3 children in the Lim family get 18 dollars a week on average. What do all 5 children get on average?
Work it out on paper, then check below. ▶ See the working
Question 9
Two classes fold paper cranes for the school's Racial Harmony Day display. The 5 pupils in Class 5 Honesty fold 20 cranes on average. All 9 pupils fold 16 cranes on average. What is the average number folded by the pupils in Class 5 Courage?
Work it out on paper, then check below. ▶ See the working
Question 10
A group of children is weighed. The average mass of the 3 boys is 47 kg. The average mass of all 5 children is 45 kg. What is the average mass of the 2 girls?
Work it out on paper, then check below. ▶ See the working
Question 11
A group of children is weighed. The average mass of the 3 boys is 46 kg. The average mass of all 8 children is 36 kg. What is the average mass of the 5 girls?
Work it out on paper, then check below. ▶ See the working
Question 12
Two teams of pupils collect donations on Flag Day. The 5 pupils in the Primary 6 team collect 53 dollars on average. The 3 pupils in the Primary 5 team collect 45 dollars on average. What do all 8 pupils collect on average?
Work it out on paper, then check below. ▶ See the working
Question 13
The cross country squad logs its training distance for the week. The average distance run by the 2 runners in the Junior squad is 46 km. The average distance run by all 8 runners is 40 km. What is the average distance run by the 6 runners in the Senior squad?
Work it out on paper, then check below. ▶ See the working
Question 14
Two classes save money for their end-of-year school trip. The 2 pupils in Room 12 have saved 28 dollars on average. The 3 pupils in Room 14 have saved 23 dollars on average. What have all 5 pupils saved on average?
Work it out on paper, then check below. ▶ See the working
Question 15
Pupils in the collectors' club count the cards in their albums. The 4 pupils who collect football cards have 50 cards on average. All 9 pupils have 45 cards on average. What is the average number of cards the animal-card collectors have?
Work it out on paper, then check below. ▶ See the working
Question 16
Two teams go bowling and record their scores. In the 5 games played by the Alpha team, the average score is 64 points. In the 4 games played by the Beta team, the average score is 55 points. What is the average score across all 9 games?
Work it out on paper, then check below. ▶ See the working